Drying installations for sludge, in particular sewage sludge are known. With such installations, the sludge to be dried is pre-dried in a preliminary stage with centrifuges until the sludge has a dry solids TS content of about 20 to 40%. Said starting material is pasty and very sticky, which complicates the handling. Now, said wet material may be burnt in an incinerator with high costs. This is accomplished at about 400° C. and is not desirable since by said method often hazardous substances, such as heavy metals are released.
A further alternative for drying the pasty starting material is the use of a so-called fluid-bed dryer which dries the mass under continuous admixing by using a hot air blower. Such installations have the disadvantages of severe sticking at the surfaces of installation parts as well as a severe odor emission into the adjacent environment whereby the quality of living is severely limited.